- Spearman's 'g' is the idea of a single general intelligence factor that underlies performance across all mental tasks.
- Thurstone emphasized multiple distinct abilities, while Cattell split intelligence into two broad types.
- Cattell-Horn-Carroll (CHC) theory is the most widely accepted scientific model of intelligence today.
- Robert Sternberg's triarchic theory proposes that intelligence has three parts: analytical, creative, and practical.
- Gardner's theory of multiple intelligences is popular in education but is scientifically contested.
What is Spearman's 'g' (general intelligence)?
Spearman's 'g' is the idea of a single general intelligence factor that underlies performance across all mental tasks. In 1904, Charles Spearman noticed that people who do well on one kind of cognitive test tend to do well on others, a 'positive manifold' he attributed to a shared general ability called g. The g factor is one of the most robust findings in psychology and remains central to nearly every modern theory of intelligence.
How do Thurstone and Cattell's theories differ?
Thurstone emphasized multiple distinct abilities, while Cattell split intelligence into two broad types. Louis Thurstone argued for several 'primary mental abilities' (such as verbal, spatial, and numerical) rather than one dominant g. Raymond Cattell instead distinguished fluid intelligence (Gf) — on-the-spot reasoning and problem-solving — from crystallized intelligence (Gc), the accumulated knowledge and skills that grow with education and experience.
What is CHC theory and why does it dominate?
Cattell-Horn-Carroll (CHC) theory is the most widely accepted scientific model of intelligence today. It organizes cognition into three levels: general g at the top, around ten broad abilities (like fluid reasoning, crystallized knowledge, and processing speed) in the middle, and many narrow skills below. CHC dominates because it is built on decades of factor-analytic data and directly shapes how modern IQ tests such as the WAIS are designed and interpreted.
What is Sternberg's triarchic theory?
Robert Sternberg's triarchic theory proposes that intelligence has three parts: analytical, creative, and practical. Analytical intelligence is the reasoning ability that traditional IQ tests measure, creative intelligence is the capacity to handle novel problems, and practical intelligence is the 'street smarts' needed to adapt to everyday contexts. It usefully broadens the concept beyond test-taking, though its creative and practical components are harder to measure reliably and remain debated.
Are Gardner's multiple intelligences scientifically valid?
Gardner's theory of multiple intelligences is popular in education but is scientifically contested. Howard Gardner proposed several independent 'intelligences' — such as musical, bodily-kinesthetic, and interpersonal — arguing they are separate from traditional IQ. Critics note that the proposed intelligences correlate with one another (consistent with g), that they look more like talents or aptitudes than separate intelligences, and that the theory has limited empirical support, so most psychometricians do not accept it as a measured model of intelligence.
Comparing Major Theories of Intelligence
| Theory | Key idea | Scientific status |
|---|---|---|
| Spearman's g (1904) | A single general factor underlies all mental ability | Robust and foundational; widely accepted |
| Thurstone's primary abilities | Several distinct abilities, not one dominant factor | Influential; partly reconciled with g |
| Cattell's Gf/Gc | Fluid reasoning vs. crystallized knowledge | Strongly supported; built into modern tests |
| Cattell-Horn-Carroll (CHC) | Three-level hierarchy: g, broad, narrow abilities | Dominant mainstream framework |
| Sternberg's triarchic | Analytical, creative, and practical intelligence | Respected but harder to measure; debated |
| Gardner's multiple intelligences | Many independent 'intelligences' | Popular in education but empirically contested |
❓ People also ask
What Is a Good IQ Score?
An IQ of 100 is exactly average; 110-119 is above average, 120 and up puts you in the top 10% (a genuinely 'good' score), and 130+ is considered gifted. IQ is built on a normal distribution with a mean of 100 and a standard deviation of 15, so most people cluster near the middle.
What Is a Good IQ Score? →IQ Percentile Chart: What Percentile Is My IQ?
Your IQ percentile tells you the share of people you scored higher than: an IQ of 100 is the 50th percentile, 115 is about the 84th, 120 is roughly the top 10%, and 130 is roughly the top 2%. The table below maps every major IQ band to its classification, percentile, and share of the population.
IQ Percentile Chart: What Percentile Is My IQ? →Are Online IQ Tests Accurate?
A well-designed online IQ test gives a reliable estimate of your reasoning ability, but it is not a clinical diagnosis — only a proctored test like the WAIS or Stanford-Binet provides that. This test is built on Raven's Progressive Matrices and CHC theory, scored on the standard scale (mean 100, SD 15), with an internal reliability (Cronbach's alpha) of about 0.85-0.92.
Are Online IQ Tests Accurate? →Can You Increase Your IQ?
You can meaningfully sharpen reasoning skills, working memory, and test performance through training and education, but raising your underlying general intelligence (g) substantially and permanently is not well supported — core g is largely heritable. The honest answer is that some gains are real and some popular claims are overstated.
Can You Increase Your IQ? →Genius IQ Level: What Number Counts as Genius?
A 'genius' IQ traditionally starts at 140, while 130 and above is labeled 'very superior' on modern tests. Scores that high are extremely rare, and the famous IQ numbers you see for historical figures are almost always estimates, not measured results.
Genius IQ Level: What Number Counts as Genius? →